The comprehensive characterization and engineering of molecular nanostructures and architectures is of great current interest, both from a scientific and technological point of view. Supramolecular chemistry at surfaces emerged over the last decade and enables the creation of a wide variety of novel and complex two-dimensionalmolecular nanosystems in vacuo or at the solid-liquid interface. This approach notably provides access to recently demonstrated new classes of coordination architectures that feature transition metal (TM) atoms in special bonding configurations, e.g., connected to molecular linkers in metal-organic coordination networks, or in self-assembled superlattices of prefabricated metal-organic complexes. The resulting arrays of surface adsorbed TM atoms can be tailored at the atomic scale and are frequently thermally robust. The incorporated TM centers themselves exhibit novel magnetic and catalytic properties that have so far largely remained unexplored and are the subject of the envisioned collaboration.